I have them both, and as usual there are good things and bad things about each. I really like HSC. It is fun and hard. HST has an obnoxious number of leg presses in it (JMHO). That said, I really love the upper body work in HST and often use the premix as an add on when I just want to do a heavier weight upper body routine. I NEVER do the lower body in HST though because of the leg presses. The other day I did all of HSC and then added on the UB premix from HST.